Red dye.



UNEKT bTA'f tlES @FFKQE.

\VALTlflR KONIG, OF 'DltESDEN, GERMANY, ASSIGNUR TO FARBENFABRIKEN VOltM. FRIEDR. BAYER J: 00., F lCiiBEltl lELl), GERMANY, A (IORPORATION OF GERMANY.

RED DYE.

Application filed November 30, 1908.

To all whom it may concern: I

Be it known that I, Walter Ktixio, doctor of technical arts, chemist, citizen of the German Empire, residing at Dresden, Suxony, Germnny, have invented new and use- 'iflil Improvements in new lied Dyes, of

which the followin is u specification. -My inwntion reliites to the manufacture and production of new red to violet basic dyestuffs which apart from their great co1- oring; power are remarkable for their very clear shades fast to washing and to light. They can be dyed on tanned cotton and are reddish a red co or..

The process for their reduction consists in treating salts of dinitrophenyliyridiniums with dihydroindols, especially dih droindol and its substitution products. T e snnie dyestulls are obtained on starting from cynnpyridiniums or from pyridins and cyanogen halogenids.

In order to illustrate the new process more fully the following example is given, the parts being: by weight: In a (lush provided with n reflux condenser 28.15 parts of 2.4.- dinitrophcnylpyridiniuni chlorid (Anna/en 333,1). 29(3) arehented onthe water bath for about 4 hours with (30 parts of methyl or ethyl nlcohol and 26.6 parts of dihydro-nlphu-methylindol Specification of Letters Patent.

reducts soluble in hot water with (see Benin/Li a (hr 1" Denise/zen U/zczmLsc/wn GcscZlxc/rrrft l t, p. 883). The crimson red 3 solution is then poured into an excess of highly diluted hydrochloric acid. The new i dyestuti is thus precipitated in the shupe of i a pulpy red mass which contains the-greater L Patented Feb. 23, 1909.

Serial No. 466,102.

part of the dinitranilin split off during the reaction. The mixture is filtered off with suction and is extracted with hot water to dissolve the dye. From the resulting red solution the d estufi is reci itnted by the addition of liyclrochloric acid or common 1 salt. It forms after being dried microscopic brownislnred needles having a blue luster which are easily soluble in alcohol, and in hot water with n red color. It dyes tanned cotton red shades resembling those of rhodomilll 6G but they are clearer and faster to li it.

Other substitution products of dihydr0 indol or dihydroindol itself may be used.

Having now described my invention and in what manner the some is to be performed, what I cluim as new and desire to secure by Letters Patent is: r

1. The herein-described new basic dyestufis obtainable from salts of dinitrophenylpyridininm and dihydroindols, especia l dihydroindol and its substitution products, which dyes are reddish products soluble in hot Wtll'tl' with a red color, and dyeing tanned cotton from red to violet shades, substantially as described.

2. The herein-described new basic dyestuff obtainable from QA-dinitrophenylpy ridiniuin chlorid and dihydro-alphm methylindol, which forms after being dried microscopic brownish-red needles, which are easily soluble in hot \VtltBl with a red color and easily soluble in alcohol with n red color and which dye tanned cotton red shades. substantially as described.

In testimony whereof I tizoom Scnnncnnmmcn, RICHARD llO'FMANN.

have hereunto set my hand in the presence of two SllbSClll)Hig- 

